Her2 genotype and breast cancer progression in Korean women

The amplification and overexpression of Her2 proto-oncogene have been found to be associated with the development and progression of human breast cancer. A polymorphic valine allele at codon 655 of the Her2 gene (Her2(V655)) was suggested by some authors to be a susceptible genetic factor for the development of breast cancer. The Her2 polymorphism at codon 655 was investigated in 304 Korean women including 177 patients with breast cancer. The association between Her2 genotype and Her2 protein overexpression was also examined in breast cancers by immunohistochemistry. Her2(V655) was not associated with a significant breast cancer risk (odds ratio (OR), 1.792; 95% confidence interval (CI), 0.459-6.991). The frequency of homozygous or heterozygous valine allele increased in stage 2 patients (OR, 1.67; 95% CI, 0.67-4.19), and patients in stages 3 and 4 (OR, 3.36; 95% CI, 0.85-13.42) compared to patients in stage 0. However, an association between the presence of the valine allele and the overexpression of Her2 protein could not be demonstrated. These results suggest that Her2 polymorphism at codon 655 is not associated with the development of breast cancer in Korean women. However, there is a possibility that the valine allele at codon 655 might be related to increased risk of breast cancer progression.     

Genome evolution during progression to breast cancer

Cancer evolution involves cycles of genomic damage, epigenetic deregulation, and increased cellular proliferation that eventually culminate in the carcinoma phenotype. Early neoplasias, which are often found concurrently with carcinomas and are histologically distinguishable from normal breast tissue, are less advanced in phenotype than carcinomas and are thought to represent precursor stages. To elucidate their role in cancer evolution we performed comparative whole-genome sequencing of early neoplasias, matched normal tissue, and carcinomas from six patients, for a total of 31 samples. By using somatic mutations as lineage markers we built trees that relate the tissue samples within each patient. On the basis of these lineage trees we inferred the order, timing, and rates of genomic events. In four out of six cases, an early neoplasia and the carcinoma share a mutated common ancestor with recurring aneuploidies, and in all six cases evolution accelerated in the carcinoma lineage. Transition spectra of somatic mutations are stable and consistent across cases, suggesting that accumulation of somatic mutations is a result of increased ancestral cell division rather than specific mutational mechanisms. In contrast to highly advanced tumors that are the focus of much of the current cancer genome sequencing, neither the early neoplasia genomes nor the carcinomas are enriched with potentially functional somatic point mutations. Aneuploidies that occur in common ancestors of neoplastic and tumor cells are the earliest events that affect a large number of genes and may predispose breast tissue to eventual development of invasive carcinoma.The cells of a multicellular organism are related to one another by a bifurcating lineage tree whose root is the zygote. DNA replication, chromosome segregation, and cell division during development from the zygote to the adult introduces point mutations and other DNA changes into the genome, which persist in the descendants of the cells in which they occurred. Germ-line point mutations occur at a rate of approximately one per diploid genome per cell division (Kong et al. 2012), but the rate of somatic changes is less well-understood, and is likely to vary by tissue type. Large-scale genomic changes such as aneuploidies are generally thought to be extremely rare in normal tissue.Cancers, in contrast to normal tissue, accumulate much larger numbers of genomic changes, as illustrated by genome sequencing of late-stage tumors (Ley et al. 2008; Stratton et al. 2009; Bignell et al. 2010; Pleasance et al. 2010a; Chapman et al. 2011; Stratton 2011; Banerji et al. 2012; Nik-Zainal et al. 2012a,b). Solid tumors are highly mutated by several mechanisms, such as point mutations, copy-number variations, and chromothripsis (Greenman et al. 2007; Leary et al. 2008; Beroukhim et al. 2010; Liu et al. 2011; Meyerson and Pellman 2011; Stephens et al. 2011; Crasta et al. 2012; Maher and Wilson 2012); relapses or metastases exhibit further mutational evolution (Ding et al. 2010, 2012; Yachida et al. 2010; Navin et al. 2011; Mardis 2012; Turajlic et al. 2012; Walter et al. 2012; Wu et al. 2012). The state of an individual advanced cancer genome sheds little light on the order of genomic changes, however, except in analyses of subclone evolution (Nik-Zainal at al. 2012a; Shah et al. 2012). In an advanced tumor, the earliest driver changes that had predisposed ancestral cells to eventual carcinoma development are confounded with later changes. As a consequence, our understanding of early tumor evolution is still in its infancy.The historically proven approach to understanding evolution is comparative analysis of extant species, whose power was greatly increased by whole-genome sequencing in recent years. Analogous to species comparisons, which are based on evolutionary (bifurcating) lineage trees, comparisons of somatic genomes from a single individual could, in principle, shed light on somatic evolution, but in normal tissue the number of mutations is low. However, given the large number of genomic changes during tumor evolution, it may be possible to dissect the evolutionary history of a cancer by comparing its genome to clinically recognized precursor lesions. In this context, breast cancers provide a proof-of-principle opportunity, due to their frequent association with early neoplastic lesions that are readily identified by morphology (Simpson et al. 2005; Abdel-Fatah et al. 2007; Lopez-Garcia et al. 2010; Bombonati and Sgroi 2011), and whose genomes may provide windows into the earliest stages of tumor evolution.Using whole-genome sequencing of histologically characterized archival (formalin-fixed, paraffin-embedded) samples, we determine lineage relationships of early neoplasias with carcinomas, quantify mutational load and mutation spectra during progression from normal tissue to neoplasia to carcinoma, and find the earliest detectable mutations and aneuploidies in cell lineages ancestral to the lesions. A subset of these early events may have provided the initial oncogenic potential and helped trigger the first clonal expansion. Our analyses reveal variation among the six cases in the specific evolution of neoplasia and tumor, as would be expected for an evolutionary process dominated by stochasticity. The mechanistic commonalities among the cases, however, bear significant implications for our conceptualization of tumor origins and progression.     

Bladder cancer: translating molecular genetic insights into clinical practice

Transitional cell (urothelial) carcinoma of the bladder is the second most common urologic malignancy and is one of the best understood neoplasms, with relatively well-defined pathogenetic pathways, natural history, and tumor biology. Conventional clinical and pathologic parameters are widely used to grade and stage tumors and to predict clinical outcome of transitional cell carcinoma; but the predictive ability of these parameters is limited, and there is a lack of indices that could allow prospective assessment of risk for individual patients. In the last decade, a wide range of candidate biomarkers representing key pathways in carcinogenesis have been reported to be clinically relevant and potentially useful as diagnostic and prognostic molecular markers, and as potential therapeutic targets. The use of molecular markers has facilitated the development of novel and more accurate diagnostic, prognostic, and therapeutic strategies. FGFR3 and TP53 mutations have been recognized as key genetic pathways in the carcinogenesis of transitional cell carcinoma. FGFR3 appears to be the most frequently mutated oncogene in transitional cell carcinoma; its mutation is strongly associated with low tumor grade, early stage, and low recurrence rate, which confer a better overall prognosis. In contrast, TP53 mutations are associated with higher tumor grade, more advanced stage, and more frequent tumor recurrences. These molecular markers offer the potential to characterize individual urothelial neoplasms more completely than is possible by histologic evaluation alone. Areas in which molecular markers may prove valuable include prediction of tumor recurrence, molecular staging of transitional cell carcinoma, detection of lymph node metastasis and circulating cancer cells, identification of therapeutic targets, and prediction of response to therapy. With accumulating molecular knowledge of transitional cell carcinoma, we are closer to the goal of bridging the gap between molecular findings and clinical outcomes. Assessment of key genetic pathways and expression profiles could ultimately establish a set of molecular markers to predict the biological nature of tumors and to establish new standards for molecular tumor grading, classification, and prognostication. The main focus of this review is to discuss clinically relevant biomarkers that might be useful in the management of transitional cell carcinoma and to provide approaches in the analysis of molecular pathways that influence the clinical course of bladder cancer.     

Chromosomal genotype in breast cancer progression: comparison of primary and secondary manifestations.

The purpose of this study was to compare the chromosomal genotype between breast cancers with and without secondary manifestations and between primary tumors and their secondary manifestations. Eighty six breast cancers, twenty lymph node metastases, ten distant metastases and ten local recurrences were analyzed by comparative genomic hybridization. Tumors with local recurrences showed significant more frequent losses at 2q32 than the tumors without recurrences. Lymph node positive cases showed significant more frequent losses at 9p21 than node negative cases. Lymph node metastases exhibited significant more frequent losses at 7q11, 14q24.3-q31 and 17q22-q24 than their primary tumors. In cases with distant metastases, losses at 5q23 were more frequent than in those without, but not reaching the significance level. The distant metastases showed significant more frequent losses at 5p15, 12q24 and 17q22-q24 than the primary tumors. These results reveal strong evidence that the potential for progression is determined in the primary tumor and that different ways of the development of local recurrences, lymph node and distant metastases exist. After confirmation of the results by interphase FISH on tissue micro arrays, the detection of these specific chromosomal imbalances may contribute to a more individual prediction of prognosis in breast cancer.     

Telomerase RNA expression during progression of gastric cancer

Telomerase, an enzyme associated with cellular immortality and malignancy, is stringently repressed in most normal somatic cells but is reactivated in malignant tumor cells and immortal cell lines, indicating that activation of telomerase may play an important role in tumorigenesis and immortalization. The pattern of human telomerase RNA (hTR) expression during progression of gastric cancer was investigated by a radioactive in situ hybridization (ISH) assay. Paraffin-embedded sections of 85 archival samples from Korean patients with benign and various malignant stages of gastric carcinomas as well as normal and regenerative tissues were studied. In normal gastric mucosae and regenerative lesions such as chronic peptic ulcer and hyperplastic polyps, only a weak degree of hTR expression was noted, and the expression was limited to basal cells of the gastric glands. Also, a moderate degree of hTR expression was present in the germinal centers of lymphoid follicles present in the submucosa. In tubular adenomas, the degree of hTR expression was also generally weak, but, unlike normal gastric mucosa, the expression was rather diffuse and occasionally focal in distribution. However, moderate to intense and usually diffuse hTR expression was present in all cancerous tissues at different stages. Although some heterogeneity of hTR expression was noted, there was a tendency for intensity of hTR expression to increase gradually as the cancer progressed to a more advanced stage. Our results indicate that upregulation of telomerase expression is associated with gastric cancer development or plays some role in gastric carcinogenesis. Upregulation of hTR expression detected by ISH assay may be a useful marker or tool for the early detection of gastric cancer.     

Promoter CpG island hypermethylation during breast cancer progression

This study was designed to evaluate the changes in promoter CpG islands hypermethylation during breast cancer progression from pre-invasive lesions [flat epithelial atypia (FEA), atypical ductal hyperplasia (ADH), and ductal carcinoma in situ (DCIS)] to invasive ductal carcinoma (IDC). We performed MethyLight analysis for the methylation status of 57 promoter CpG island loci in 20 IDCs and their paired normal breast tissues. After selecting 15 CpG island loci showing breast cancer-specific DNA methylation, another set of normal breast tissue (n = 10), ADH/FEA (n = 30), DCIS (n = 35), and IDC (n = 30) of the breast were analyzed for these loci. We found six new methylation markers of breast cancer, namely DLEC1, GRIN2B, HOXA1, MT1G, SFRP4, and TMEFF2, in addition to APC, GSTP1, HOXA10, IGF2, RARB, RASSF1A, RUNX3, SCGB3A1 (HIN-1), and SFRP1. The number of methylated genes increased stepwise from normal breast to ADH/FEA and DCIS, while IDC did not differ from DCIS. Methylation levels and frequencies of APC, DLEC1, HOXA1, and RASSF1A promoter CpG islands were significantly higher in ADH/FEA than in normal breast tissue. GRIN2B, GSTP1, HOXA1, RARB, RUNX3, SFRP1, and TMEFF2 showed higher methylation levels and frequencies in DCIS than in ADH/FEA. DICS and IDC did not differ in the methylation levels or frequencies for most CpG island loci except SFRP1 and HOXA10. Our findings showed that promoter CpG island methylation changed significantly in pre-invasive lesions, and was similar in IDC and DCIS, suggesting that CpG island methylation of tumor-related genes is an early event in breast cancer progression.     

The clinical efficacy of Bladder Chek NMP22 in urothelial cancer

The purpose of this study is to investigate the clinical efficacy of a quick test for NMP22 (Nuclear Matrix Protein 22), Bladder Chek NMP22, as a screening test for urothelial cancers. The subjects include 51 cases(43 cases with pathologically confirmed bladder cancer, and 8 cases with upper urothelial cancer). Bladder Chek NMP22 revealed false positive in the urine with more than 1 x 10(5)/microliter of erythrocytes and 1 x 10(3)/microliter of white blood cells. Thus, showing that Bladder Chek NMP22 was not relatively affected by the contaminated erythrocytes and white blood cells, compared with other conventional methods to detect urinary malignant disease. In 51 cases diagnosed of having pathologically urothelial cancers, the sensitivity of Bladder Chek NMP22 was 56.8%. Bladder Chek NMP22 demonstrated more excellent sensitivity than the other methods. The positivity of Grade3 patients was 68.4%, 68.4% and 63.2% by Bladder Chek NMP22, NMP22 ELISA and urinary cytology. In contrast, the positivity rate for the patients with Grade1 stage was 58.3%, 33.3% and 8.3%. There is no significance of positivity rate between each examination in patients with high grade cancer. However Bladder Chek NMP22 demonstrated the higher positivity in patients with low grade cancer. Bladder Chek NMP22 test could be an easy and confidential method to detect urothelial cancers, especially with low grade, as a screening examination.     

Changes in retinoblastoma gene expression during cervical cancer progression

The role of tumour suppressor genes in the development of human cancers has been studied extensively. In viral carcinogenesis, the inactivation of suppressor proteins such as retinoblastoma (pRb) and p53, and cellular oncogenes overexpression, such as c-myc, has been the subject of a number of investigations. In uterine-cervix carcinomas, where high-risk human papillomavirus (HPV) plays an important role, pRb and p53 are inactivated by E7 and E6 viral oncoproteins, respectively. However, little is known about the in situ expression of some of these proteins in pre-malignant and malignant cervical tissues. On the other hand, it has also been demonstrated that c-myc is involved in cervical carcinogenesis, and that pRb participates in the control of c-myc gene expression. By using immunostaining techniques, we investigated pRb immunodetection pattern in normal tissues, squamous intraepithelial lesions (SILs) and invasive carcinomas from the uterine cervix. Our data show low pRb detection in both normal cervical tissue and invasive lesions, but a higher expression in SILs. C-Myc protein was observed in most of the cellular nuclei of the invasive lesions, while in SILs was low. These findings indicate a heterogeneous pRb immunostaining during the different stages of cervical carcinogenesis, and suggest that this staining pattern could be a common feature implicated in the pathogenesis of uterine-cervix carcinoma.     

Causal pathways for CCR5 genotype and HIV progression

A homozygous 32-bp deletion in the gene encoding CCR5, a major coreceptor for HIV-1, leads to resistance to infection with HIV-1, and heterozygosity for the deletion is associated with delayed disease progression in persons infected with HIV-1. We investigated the effect of CCR5 heterozygosity on disease progression as measured by both CD4+ T-cell count decline and the occurrence of clinical AIDS symptoms. Using a unified statistical model for CD4 count progression and AIDS development, we examined whether the effect of CCR5 heterozygosity on clinical AIDS is direct or indirect through its effect on CD4 counts. Based on data from the Multicenter AIDS Cohort Study, we noted a protective effect of CCR5 heterozygosity on both CD4 cell count progression and on AIDS occurrence. Furthermore, we found that this protective effect on the occurrence of AIDS was completely mediated through an effect on the CD4 marker. Additional adjustment for the effect of an initial viral load measurement indicate that CCR5 heterozygosity did not have predictive value for either CD4 progression or the development of AIDS beyond its association with early viral load.     

Geminin predicts adverse clinical outcome in breast cancer by reflecting cell-cycle progression

Geminin inhibits DNA replication by preventing Cdt1 from loading minichromosome maintenance (MCM) proteins onto DNA. The present study has investigated whether the frequency of geminin expression predicts clinical outcome in breast cancer. Immunohistochemistry was used first to examine geminin expression in normal and malignant breast tissue (n = 67). Correlations with cell-cycle parameters, pathological features, and clinical outcome were then determined using an invasive breast carcinoma tissue microarray (n = 165). Breast carcinomas were scanned for mutations (n = 61) and copy number imbalances (n = 241) of the geminin gene. Finally, the cell cycle distribution of geminin in breast cancer cells was investigated in vivo and in vitro. Despite a putative tumour suppressor function, it was found that increased geminin expression is a powerful independent indicator of adverse prognosis in invasive breast cancer. Both poor overall survival (p = 0.0002) and the development of distant metastases (p = 0.005) are predicted by high geminin expression, which performs better in this patient cohort than traditional factors currently used to determine prognosis and appropriate therapy. No mutations or deletions of the geminin gene and no evidence that a high frequency of protein expression is related to gene amplification were found. It is shown that geminin is expressed from S to M phase in breast carcinoma tissue and cell lines, disappearing at the metaphase--anaphase transition. While MCM proteins identify all non-quiescent cells, geminin identifies the sub-fraction that have entered S phase, but not exited mitosis, thereby indicating the rate of cell-cycle progression. It is suggested that this explains its unexpected value as a prognostic marker in breast cancer.     

Sequential activation and production of matrix metalloproteinase-2 during breast cancer progression

The proteolytic processes are thought to be the critical point in tumor invasion and metastasis, mainly by matrix metalloproteinases (MMPs) and serine proteases. We measured the activity of MMP-2 from 28 normal, 12 benign and 126 breast cancer tissues using gelatin zymography. Inactive MMP-2 (72 kD) was expressed in 53.6% of the normal and 66.6% of the cancer tissues, respectively (P= 0.77), while active MMP-2 (62 kD) was expressed in 28.6% and 73.0%, respectively (P = 0.003). The enzymatic activity of active MMP-2 (62 kD) measured in the gel band area was 4.0 ± 7.2 mm² in normal breasts, 7.7 ± 9.8 mm² in benign breast diseases, 9.5 ± 8.5 mm² in ductal carcinoma in situ (DCIS), and 12.0 ± 13.7 mm² in invasive cancers. The MMP-2 activation ratio (62 kD/62 kD + 72 kD) was 0.12 ± 0.18 in normal tissues, 0.10 ± 0.20 in benign diseases, 0.61 ± 0.22 in DCIS, and 0.50 ± 0.28 in invasive cancers. In conclusion, MMP-2 activation was the main cause of the increased 62 kD MMP-2 activity during the early phase of breast cancer, while production of MMP-2 supplemented the increased 62 kD activity in the late phase. We suggest, therefore, that these differential expressions of MMP-2 activation and production during the different stages of breast cancer progression are potential therapeutic targets for biological or gene therapy under the concept of stage-oriented cancer treatment.[]     

Bladder cancer epidemiology and genetic susceptibility

Bladder cancer is the most common malignancy of the urinary system. The incidence of bladder cancer of men is higher than that of women (approximately 4:1). Here, we summarize the bladder cancer-related risk factors, including environmental and genetic factors. In recent years, although the mortality rate induced by bladder cancer has been stable or decreased gradually, the public health effect may be pronounced. The well-established risk factors for bladder cancer are cigarette smoking and occupational exposure. Genetic factors also play important roles in the susceptibility to bladder cancer. A recent study demonstrated that hereditary non-polyposis colorectal cancer is associated with increased risk of bladder cancer. Since 2008, genome-wide association study (GWAS) has been used to identify the susceptibility loci for bladder cancer. Further gene-gene or gene-environment interaction studies need to be conducted to provide more information for the etiology of bladder cancer.     

Sibship stability of genotype and phenotype in myotonic dystrophy

Myotonic dystrophy (DM1) is caused by an unstable CTG repeat expansion. Despite the evidence of birth order effect in congenital DM1, the expansion's dynamics among sibships is still unknown. The objective of this study was to determine phenotype and CTG repeat size variability in DM1 sibships, and to investigate their predictive values. We compared 86 sib pairs for CTG repeat, 61 for age at onset and 89 for DM1 phenotype. CTG repeats remained stable for 66 of the 86 sib pairs, including 25 of 27 maternal transmissions and 30 of 42 paternal transmissions. Variations of less than 10 years in the age at onset were observed in 44 of 61 sib pairs, including 16 of 18 maternal transmissions and 19 of 28 paternal transmissions. The same phenotypic severity or a variation of only one class was observed among 86 of the 89 sib pairs, including all of the 35 maternal transmissions and 30 of the 33 paternal transmissions. Birth order, intergenesic interval, oldest sib's CTG repeat or parental age and CTG repeat did not exert any significant influence. These results suggest that genotype and phenotype remained stable among sibs, although the paternal origin of the mutation seemed to reduce the predictability of the severity.     

Differentially expressed genes in two LNCaP prostate cancer cell lines reflecting changes during prostate cancer progression

Prostate cancer tends to become transformed to androgen-independent disease over time when treated by androgen-deprivation therapy. We used two variants of the human prostate cancer cell line LNCaP to study gene expression differences during prostate cancer progression to androgen-independent disease. Production of prostate-specific antigen was regarded as a marker of androgen-dependence and loss of prostate-specific antigen was regarded as a marker of androgen-independence. mRNA from both cell lines was used for cDNA microarray screening. Differential expression of several genes was confirmed by Northern blotting. Monoamine oxidase A, an Expressed Sequence Tag (EST) similar to rat P044, and EST AA412049 were highly overexpressed in androgen-dependent LNCaP cells. Tissue-type plasminogen activator, interferon-inducible protein p78 (MxB), an EST similar to galectin-1, follistatin, fatty acid-binding protein 5, EST AA609749, annexin I, the interferon-inducible gene 1-8U, and phospholipase D1 were highly overexpressed in androgen-independent LNCaP cells. All studied genes had low or no expression in PC-3 cells. The EST similar to rat P044, the EST similar to galectin-1, follistatin, annexin I, and the interferon-inducible gene 1-8U were also expressed in benign prostatic hyperplasia tissue. The Y-linked ribosomal protein S4, Mat-8, and EST AA307912 were highly expressed in benign prostatic hyperplasia tissue. Additionally, both confirmation of differential expression in Northern blots and in situ hybridization were carried out for monoamine oxidase A, the EST similar to rat P044, the EST similar to galectin-1, fatty acid-binding protein 5, and the interferon-inducible gene 1-8U. We identified several potential prostate cancer markers, indicating that the method used is a useful tool for the screening of cancer markers, but other methods, such as in situ hybridization, are needed to further investigate the observations.